Apparatus for jacking airplanes or the like



Feb. 13, 1945.

P. A. DUNN, JR

APPARATUS FOR JAGKING AIRPLANES OR THE LIKE Filed March 50, 1942 INVENTOR am w, ggum WEBB-13,1945

APPARATUS FOR JACKING AIBPLANES OR THE LIKE Paul A. Dunn, In, Kenmore, N. Y.

Application March 30, 1942, Serial No. 436,750

5Claims.

This invention relates to lifting devices. and more particularly to a novel type of lifting jack which is especially adapted to lift an airplane undercarriage strut or the like in connection with the repair or replacement of the airplane wheels.

gedness and which is in the nature of a readily portable tool adapted to be coupled to an airplane undercarriage strut or the like in improved manner. Another object of the invention is to provide a device of the character, described which is adapted to be manipulated to elevate the member to which it is connected in improved manner. Another object of the invention is to provide a device of the character described which is adapted to be coupled to an airplane undercarriage strut or the like so as to become a rigid extension thereof whereby to obviate 'the possibility of toppling of the jack device or of the elevated strut member relative to the jack device when the apparatus is in work-lifted condition. Another object of the invention is to provide a lifting jack device of the character described which is adapted to be coupled to a vertical strut member or the like by means of vertically spaced connection devices whichpermit rotation of the jack device relative to the connection devices subsequent to initial coupling of the jack device to the member to be lifted and preliminary to final locking together thereof. Other objects and advantages of the invention will appear in the specification hereinafter.

In the drawing:

Fig. 1 is a fragmentary front elevation of an airplane landing wheel strut having a jack of the invention coupled thereto and holding the strut in lifted position to illustrate the principles involved;

Fig. 2 is a section, on an enlarged scale, taken along line II-1I of Fig. l;

Fig. 3 is a fragmentary elevation, on an en-- larged scale, corresponding to Fig. l and showing another form of one of the lack connection devices;

Fig.4 is a view similar to Fig. 3 of another mode of coupling the Jack to the object to be lifted; and 1 Fig. 5 is a view similar to Fig. 2 showing another form of jack connection device.

The drawing illustrates the-invention in con- Junction witlra generally vertically extending its upper end portion in telescopic relation withma shock absorbing cylinder mechanism It, as is customary in modem'airplane. design. The

strut Ill includes a vertically disposed intermediate body portion ll terminating at its lower end in a perpendicularly disposed axleportion l5 having a spindle l6 mounted therein and carrying a wheel ll. As illustrated in Figs. 1 and 3, the axle portion I! is usually provided with a downwardly extending boss I 8 for anchoring connection upon the work contacting pad portion of a conventional lifting jack or the like. However, it will be understood that whenever a conventional type jack is set below the axle portion of amundercarriage strut and manipulated so as to lift the latter beyond wheel-ground contacting position, the jack bears upwardly against the bottom of the strut and is entirely unbraced against toppling deflection away from an atti-' tude of straight-line alignment therewith. Consequently, whenever a conventional lifting jack is employed in the manner described the lifted member is highly unstable thereon and the jack is free to wobble ,laterally in any direction es- 257 cept as it may be restricted therefrom by reason designated at 25.

of the lateral extent of its base formation. Ob-- viously, the base portion of a portable lifting Jack may, as a practical matter, be extended in lateral directions to only a limited'degree; and hence whenever a conventional type jack is employed to lift against a vertically extended strut or the like the result is invariably a highly unstable condition.

In the case of the present invention a lift dea' vice of any suitable form is employed in conjunction with a plurality of connection devices extending laterally therefrom for adjustable connection with respect to the object to be lifted at a plurality of vertically spaced connection points. For example, as illustrated in the drawing, the lift device is illustrated as comprising a hydraulic cylinder 29 carrying atelescoplc ram 22 to extend from one end thereof and to bear against a foot plate 24 adapted to rest upon the ground It will be understood that the ram 22 connects to a piston (not shown) carried within the cylinder 20 for control thereof through development of pneumatic or hydraulic pressure forces within the cylinder resulting from manual operation of a pump device as indicated at 26 arranged to be actuated by means of a handle 28.

It will be understood however that any other suitable type of lifting jack mechanism may be airplane landing wheel strut l8 which extends at as employed in lieu of the hydraulic type illustrated ably embracing the cylinder II and carrying at one side a locking bolt 34 arranged to be manipulated by means of a handle I. The bracket It a also includes a laterally extending step portion ll which is generally trough shaped to engage in cradling relation against the lower surface of the member to be lifted. The step It is perforated as indicated at 38 to receive the boss I! in keying relation therein in case a boss of the type referred to isprovided on the strut to be lifted. Adjacent its upper end. the jack cylinder car- .ries a second bracket 40 comprising essentially an eye portion adapted to slidably engage about the cylinder and having split flange portions 42 extending at one side thereof to receive a locking bolt 44 arranged to be rotated by means of a handle I. At its opposite side the bracket 40 carries an eye 4. adapted to beinserted between opposed lug portions 48 extending from the un dercarriage strut Ill and perforated so that a mountingpin 49 may be inserted therethrough to engage the bracket 40 in laterally fixed relation with respect to the strut to be lifted.

Thus, it will be understood that th I brackets "-40 are normally carried by the lifting jack mechanism as integral portions thereof while being readily adjustable longitudinally and rotationally relative thereto. Hence, whenever it is desired to install the jack in operation for lifting a member such as the airplane wheel strut of Fig. 1, the jack will be disposed in side-by-side relation with respect to the strut end portion l4 whereupon the brackets of the lack may be readily adjusted vertically and/or rotated relative to the housing 20 so as to be arranged in conjunction with the strut as illustrated by Fig. l; and it will be appreciated that the extreme adjustability of the bracket devices enables the jack of the invention to lift an object from any given point above the ground level. The clamping bolt handles may then be manipulated so as to clamp the brackets in rigidly fixed rela tion upon the jack device,. and the strut I. may then be readily'elevated by simply pumping the hydraulic pump device 28, or by manipulating the jack actuating mechanism as may be provided in any other case. The plate 24 is dimpled at spaced intervals as indicated at ll to provide sockets therein to receive the jack ram 22 'at any adjusted position. Also, the dimpled portions constitute anti-skid elements for pressing downwardly into the ground whereby the plate-is prevented frorn skidding out of operation position.

It will be appreciated that by'reason of the novel method of mounting the jack mechanism upon the airplane strut, the jack device will be thereby coupled to the strut in the manner of a rigid extension integral therewith; and that upon actuation of the lack extension mechanism the ram 22 will ress downwardly against'the ground surfaceso as to provide the requisite force reaction for lifting the airplane wheel I! out of contact with the ground. It will also be appreciated that by reason of the rigid mounting of the jack mechanism upon the airplane strut II at the and described hereinabove, the danger of toppling of the jack member relative to the airplane strut i0 is completely obviated, and the lifted strut and lifting jack unit comprises a sinale and rigid structure whereby stable support of the airplane upon the jack is absolutely ascured.

It will'of course be understood that the connection devices employed to couple the lifting jack to the lifted member may vary in detail in order to suit different conditions of operationand to adapt the connecting bracket devices to different forms of members to be lifted. For example, as illustrated in Fig. 3, the lower bracket member may comprise an eye portion 50 slidably engaging the body of the jack and carrying a clamping screw or lock arrangement as indicated at 5244. A foot portion II extends laterally from the bracket eye and is recessed in its upper surface as indicated at 58 so as to be adapted to engage in complementing fashion against the rounded lower surface portion of the axle Iii when the jack foot is disposed to extend in directions transversely of the axis of the axle. Thus, the foot portion 55 may be usefully employed to couple the lifting jack to'theaxle it whenever it is preferred to dispose the jack either in front of or behind the wheel strut I, as distinguished from in a position at one side thereof as illustrated in Figs. 1 to 3. An auxiliary plate 58 may be provided with an eye portion 59 at one end thereoffor encircling the jack member 20, and the plat is arranged to extend in seated relation upon the upper surfaces of the bracket 55 to engage against the under surface of the axle I5 when the jack is arranged at one side of the wheel strut. The plate 58 is perforated as indicated at 80 to receive in keying relation the boss I! extending fromthe wheel strut;

40 As illustrated in Fig. 4,'the axle portion is of the airplane wheel strut may be engaged by -a bracket 84 generally gsirnilar to the bracket 55 of Fig. 3. The bracket 84 is perforated as at to receive the boss which may be formed to ex-, tend below thei'nemberto be lifted. The upper bracket 8 of Fig.4 ljslgenerally similar in form to the bracket "(of Figs. 1 and 2, and the lugs 4 H! for carrying the coupling pin-49 are formed ferred not to have lug or eye portions formed integrally-with the member to be lifted, as for example the eyeportions 48-48 of Figs. 1 and 4, the bracket coupling the upper end of the jack device to the member to.be lifted may be formed as illustrated in Fig. 5 to include an encircling collar 'llla'dapted to fit about the member to be lifted inythe manner of a looped band of metal or the likezfor' coupling the upper end of the lifting jack to the member to be lifted. Thus, the coupling device may be readily adjusted upon the strut to any desired vertical position and upon operation of the device the novel features of stability under lifted conditions are obtained as explained hereinabove.

It will be understood that in some cases it may be advisable to rotate the jack device axially relative to the coupling brackets thereof so as vertically spaced points jf connection as fllugto turn the jack actuating handle 28 01 other portions thereof away from positions of interference with extending portions of the airplane or the like; and that this effect may be readily obtained by simply turning the jack member about its longitudinal axis relative to its coupling brackets prior to final clamping of the brackets thereon. Thus, it will be appreciated that by reason of the lifting jack and bracket arrangement of the invention optimum selectivity of the mode of coupling of the lifting jack to the member to be lifted is provided to suit a large variety of operating conditions. Also, it will be appreciated that subsequent to repair of the airplane, or for whatever purpose the object has been lifted, the lift mechanism may be released by manipulation of the control mechanism thereof for lowering of the elevated object while the lift device remains rigidly clamped thereto in such manner as to provide the improved stability features referred to hereinabove; and that therefore the jack'device of the invention is adapted to be employed with extreme facility in connection with a. large variety of uses and in every case to provide the improved stability under lifting I conditions referred to.

Although only a few forms of the invention have been shown and described in detail, it will be apparent to those skilled in the art that the invention is not so limited but that various changes may be made therein without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A lift jack for elevatingvertically extending members comprising an extensible lift jack device including an elongate housing, a ram adapted to move longitudinally of said housing to provide lifting action by said jack, a plurality of coupling members vertically slidably mounted upon said housing to extend laterally therefrom and adapted to be connected to the member to be lifted at vertically spaced positions therealong to transmit thereto from said housing lifting forces and lateral bracing forces for maintaining said housing in predetermined alignment relation with the member to be lifted.

2. A lift jack comprising an extensible strut device including relatively movable members, a lift step slidably mounted upon one of said members to extend laterally therefrom and adapted to bear upwardly against a portion of the object to be lifted, and a coupling device extending from said one of said members at a vertically spaced position from said lift step and adapted to engage another vertically spaced portion of the object to be lifted to relatively brace said object and said jack laterally against displacement from a predetermined lifting aligned relation thereof.

3. A lift jack comprising an extensible strut device including relatively movable members, a plurality of coupling devices slidably mounted upon -one of said members to extend laterally therefrom and adapted to be connected to the object to be lifted at vertically spaced positions therealong, said coupling devices being adjustable relative to said one of said members between clamped and unclamped positions thereon and freely pivotable in directions transversely of the direction of lifting movement when in unclamped condition, one of said coupling devices being a lift step adapted to bear upwardly against a portion of the object to be lifted and the other of said coupling devices being a lateral brace member adapted to couple to the object to be lifted to relatively brace the object and said jack in lateral directions.

4. A lift device for elevating objects comprising an extensible strut device including relatively movable members, a plurality of connectors slidably mounted upon one of said members to extend laterally therefrom and adapted to be connected to the object to be lifted at vertically spaced positions therealong, one of said coupling devices being a lift step adapted to bear upwardly against a portion of the object to be lifted and the other of said coupling devices being a lateral brace member adapted to couple to the object to be lifted to relatively brace the object and said jack in lateral directions.

5. A lift jack for elevating objects comprising an extensible lift jack device including relatively movable members, a pair of coupling devices slidably and pivotally mounted upon one of said members toextend laterally therefrom and adapted to be connected to the object to be lifted at vertically spaced positions therealong, and means for clamping said coupling devices to said member in rigidly extending relation thereon subsequent to such connection, one of said coupling devices being a lift step adapted to bear upwardly against a portion of the object to be lifted and the other of said coupling devices being a lateral brace member adapted to couple to the object to be lifted to relatively brace the object and said jack in lateral directions.

PAUL A. DUNN, JR. 

